Some had travelled the length of Britain to London while others had even come from abroad to witness what they called "a little piece of history".

By late last night, helped by the attractions of the Victoria Monument fountains on the hottest day of the year in the capital, the crowds outside Buckingham Palace had swelled into the hundreds as they awaited the official announcement that a future monarch had been born.

Some had brought champagne, many others had Union flags.

They had gathered in the expectation that they would be first to learn of the news of a royal birth when, according to protocol, the news was posted on an easel outside the palace.

Last night it emerged that the news would first be announced in a press release, but it seems to have done little to dampen the spirits of those outside.

When the easel was finally placed outside the palace, the announcement was greeted with cheers.

Tristan Walker (30), who is visiting from Australia, said: "We are so happy to be here. We saw everyone running towards the gates so we ran, too."

Leo Freeman (49), a sign language interpreter from south London, said: "I'm delighted. Everyone expected it to be a girl I think. It's a great atmosphere."

There were shouts of "it's a boy" and "congratulations Will and Kate".

The news that a future king had been born was greeted with jubilation among the hundreds of well-wishers gathered outside St Mary's Hospital.

Cheers of "hip-hip hooray" rang out as the news quickly spread.

Many of those who had endured hours in scorching temperatures danced in the street singing 'Happy Birthday' and 'Congratulations'.

A town crier also appeared on the steps of the Lindo Wing to formally congratulate the royal couple.